Cumulus: Detached domes or towers which are
usually dense and well defined; develops vertically in the form of rising mounds
of which the bulging upper part often resembles a cauliflower; composed of a
great density of small water droplets, frequently supercooled; larger drops
often develop within the cloud and fall from the bases as trails of evaporating
rain (virga); ice crystals sometime form in the upper portion and grow larger by
taking water from the water droplets; maximum frequency and development in the
afternoon over land and during the night over water.

Cumulus congestus: Cumulus clouds that show
extensive vertical development. They may form in rows, such as these, or
as individual clouds that appear as a head of cauliflower. Showery
precipitation may fall from cumulus congestus. This type usually develops
very rapidly into the cumulonimbus.

Cumulus types: The clouds with much smaller
vertical extent are called cumulus humilis. This cloud is an
indication of fine, fair weather. The very small
ragged-looking clouds are called cumulus fractus. These clouds are
broken by turbulence.

Cumulonimbus: Heavy and dense cloud, with a
considerable vertical extent, in the form of a mountain or a massive tower;
often with tops in the shape of an anvil or vast plume; base of cloud often very
dark with low ragged clouds either merged with it or not; frequently accompanied
by lightning and thunder, and sometimes hail; occasionally produces a tornado or
a waterspout; the ultimate manifestation of the growth of a cumulus cloud,
occasionally extending well into the stratosphere.

Mammatus: Downward moving air causes these clouds
to hang from the base of another cloud - most often a cumulonimbus or an
altostratus. This type of "boiling" cloud appears at the beginning of a
squall or just before.